Java fundamentals

Question 1

JAVA Character Set

Answer 1

Character set is a set of valid characters that a language can recognise.
A character represents any letter, digit or any other sign.

Java uses the Unicode character set.

Unicode is a character coding scheme that has character codes for numbers, arithmetic symbols, special characters and for the letters in almost all the languages in the world.

Question 2

Tokens

Answer 2

The smallest individual unit in a program is known as a token.

Java has the following tokens:

• Keywords
• Identifiers
• Literals
• Operators
• Separators

Question 3

Keywords

Answer 3

• Keywords are reserved words.
• Keywords are words that convey special meaning to the compiler.
• THey aer not to be used as names of variablres.

Question 4

Identifiers

Answer 4

• Identifiers are names given to different parts of the program such as variables, classes, functions, arrays, etc.

Question 5

Identifier forming rules of Java

Answer 5

• Can have alphabets, digits, underscores and dollar sign.
• Must not be a keyword, Boolean literal(like true and false) or null literal(like null)
• Must not begin with a digit.
• Java is case sensitive i.e upper-case letters and lower case letters are treated differently.
• Must not have spaces.

Question 6

Literals

Answer 6

• Literals are data items that have fixed data values.
• Types:
  • Integer literals
  • Floating literals
  • Boolean literals
  • Character literals
  • String literal
  • Null literal

Question 7

Operators

Answer 7

Operators are tokens which perform specific operations on data.

Examples:

• Arithmetic operators
• Relational operators
• Logical operators

Question 8

Separators

Answer 8

() - parenthesis
{} - curly braces
[] - square brackets
; - semi colon
, comma
. dot